In decentralized networks, for example peer to peer overlay networks based on a distributed hash table, resources are distributed to the individual network nodes in a decentralized manner. It is possible in this process for each individual network node to search for corresponding resources with the aid of keywords. Checking values are used for this purpose, with a unique checking value being generated from a keyword. The checking values are managed by the network nodes, with each network node being responsible for predetermined checking values. Each of the network nodes is allocated a unique identifier from a key space. This can be a binary key space for example with a width of n bits. The checking values, which are likewise formed for example from the key space with a width of n bits, are used by network nodes to direct search requests for example into the network. A network node can also send so-called publication requests for a specific checking value to the network node responsible for the specific checking value. The transmitting network node uses such publication requests to give notice that it wishes to publish, in other words make available to the other network nodes, resources, which are assigned to the specific checking value and as a result to the corresponding keyword, in the network.
The checking values are for example hash values, which are generated using a hash algorithm. The checking values are preferably stored in a table, with each table entry containing a corresponding checking value and data assigned to this checking value, for example a reference to the storage location of corresponding resources.
This data is associated here with the keyword, from which the checking value was generated. The table is preferably distributed in a decentralized manner in the data network, with each network node being responsible for a value range in the table.
The instance can now occur that specific resources, in other words specific checking values, are requested, in particular searched for and/or published, particularly often by means of corresponding requests in the network. This results in overloading of the network nodes responsible for the corresponding checking values. Such network nodes are also referred to as hot spots. When a hot spot is overloaded, it can cause blocking and failure of said network node. As a result the network traffic in the region of this hot spot increases, endangering the stability of the network as a whole. The network also loses capacity.
To resolve the hot spot problem, it is known from the prior art that particularly popular data can be replicated to one or more network nodes. For example the popular data, for which a corresponding network node is responsible, can be replicated directly to adjacent nodes. Replication to any other network nodes, for example those specified by algorithms, is also possible however. However data replication poses the problem that it must always be ensured in the network that the replicated copies are up to date. This requires further specific mechanisms.
It is also known that a further logical network can be provided for the data network, to organize the requests in the network. This has the disadvantage that so-called “keep alive” messages are required, with the result that a relatively extensive transmission capacity bandwidth is taken up by the further logical network alone. It is furthermore necessary to manage connections, using the existing table that is distributed in a decentralized manner in the data network.